The banner petal of a Calobota sericea flower is wide and rounded, pleated down the centre and curved forward in a slight hood-shape. It may also, while still curving forward in the petal blade, be flexed or curving back at the base, away from the other petals.
The keel is narrow, paler coloured here than the rest of the corolla and longer than the wings flanking it. The calyx is darker grey than the leaves and cup-shaped; its tiny lobes thin, pointed and well-spaced.
The flowers grow on short stalks, sometimes curved (Manning, 2007; iNaturalist).